IV PREFACE. 



and general. Such a sketch, however amplified, could never 

 take the place of a Flora, or System of Plants, but is de- 

 signed merely to give a general idea of the distribution of 

 the vegetable kingdom into families, &c., with a cursory no- 

 tice of their structure, properties, and principal useful pro- 

 ducts. In applying the principles of classification, and his 

 knowledge of the structure of plants, to the investigation of 

 the plants that grow spontaneously around him, the student 

 will necessarily use some local Flora, such, for example, as 

 the author's Manual of the Bolany of the NorUierri United 

 States. For particular illustrations the botanist may ad- 

 vantageously consult the author's Genera of the Plants of 

 the United States illustrated by Figures and Analyses from 

 Nature, of which two volumes have been published. 



About twenty-four of the wood-cuts are, by permission, 

 selected from original sketches made for a Report on the 

 Trees of the United States, in preparation by the author for 

 the Smithsonian Institution. The numerous figures added 

 to this edition are wholly of an original character. 



The numerals enclosed in parentheses, which abound in 

 the pages of this work, are references to other and mostly 

 earlier paragraphs, in which the subjects or the terms in 

 question are treated of or explained. 



A full Glossary or Dictionary of Botanical Terms (com- 

 bined with an Index) is added to the volume. In this, it 

 is thought, the student will find explanations of all the 

 technical botanical terms he is likely to meet with in descrip- 

 tive works, written in the English language. The Avords 

 are here accentuated, in all cases where this seemed to be 

 needful. 



Harvard University, Cambridge, Sept. 1857. 



